Robert Khan and Tom Salinsky have tried their hands at writing and their first play is “Coalition,” which is presently established in the Pleasance Dome. Although a debut effort, “Coalition” is as grand and as slick as the Edinburgh Tattoo. The play is currently sold out until Monday and the big names on the cast include Phill Jupitus and Jo Caulfield.

Portraying the political downfall of a barely-fictional Lib Dem leader, who is trying to square his party’s “principles” with the realities of Coalition government, “Coalition” is pitched carefully between the BBC sitcoms “Yes Minister” and “The Thick of It.” “Yes Minister” had observed how high office always compromises political leadership, whilst “The Thick of It” had dealt with a tier of political advisers and also-ran politicians who were safely contained under a glass ceiling. Matt Cooper (Thom Tuck), a Lib Dem leader in the very same shoes as Nick Clegg, is supposed to be running the country but he is actually more wretched than the insects in TTOI. Unlike in TTOI, however, the PM (Simon Evans) eventually makes a brief, sinisterly beneficent appearance.

Thom Tuck evidently models Cooper upon Basil Fawlty and the Lib Dem leader is lurching from one crisis to the next, whilst never being short of a viciously exasperated remark, whether it is about Lib Dem students (“fucking loonies”) or former Lib Dem leaders (“the colonel, the pensioner or the soak”). His PA (Jessica Regan) supplies the common sense, just as the more practical Polly had tried to provide damage limitation for Basil.

With his rubbery face and squeaky voice, Cooper also looks and sounds very much like the Tory minister Michael Gove, whilst something of Jeremy Hunt’s fixed awkward smile has rubbed off on Copper’s “protégée” Eddie (Phil Mulryne). The political class has been henceforth blended up together and fictional Lib Dems have been reconstructed from scraps of real Tories. When Jupitus is on stage, it is as if the sun has come out, but his deliciously beastly Tory fixer is likewise based upon Labour’s Peter Mandelson.

The writing is superbly effective and the audience is often weeping over the play. There is spontaneous applause between scenes and they are laughing to themselves even after the cast have trooped offstage. Yet whilst the jokes are invariably at the expense of how useless the Lib Dems are and how ruthless the Tories, this play proves oddly sympathetic to Nick Clegg, or rather it assents to a fatalistic acceptance of the impossible circumstances in which he finds himself. An agitating Lib Dem minister (Alistair Barrie) with a toe in the grassroots, who is clearly some shade of Vince Cable, prefers the Liberals’ traditional anti-establishment sentimentality to the unpopularity of government. Cooper has to appease both this wayward minister and the governing Tories. “Coalition” seems to define political principle as being just a sort of pointless awkwardness and the play ends with the Tories sweeping to power.

“Coalition” explores a scenario which we are already far too familiar with. Most people are thoroughly sick of Nick Clegg and the country is now waiting for him to receive his comeuppance in the next election. “Coalition” may offer a cathartic sneak peek at Clegg’s downfall, but it is dangerous to make predictions in politics. This play spells doom for Nick Clegg, but if it turns out to be wrong then a fine piece of theatre will be left as discredited as Clegg’s own fictional counterpart.